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Book .1^ ; 




Issued February IG, 1914. 

|S, DEPARTMENT OF AGRICULTURE, 
''BUREAU OF ANIMAL INDUSTRY. 
A. D. MELVIN. Chief of BuREAr. 



THE OPHTHALMIC TEST 
FOR GLANDERS 




WASHINGTON; 
GOVERNMENT PRINTING OFFICE. 

1914. 



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Y ,; Issued February 16, 1914. 

U. S. DEPARTMENT OF AGRICULTURE, 

BUREAU OF ANIMAL INDUSTRY. 
A. D. MELVIN, Chief of Bureau. 



THE OPHTHALMIC TEST FOR GLANDERS. 

During the past few years the ophthalmic maliein test 
has gained great favor in the diagnosis of glanders. The 
popularity of the test is rapidly gaining wherever this 
method has been applied, and among its supporters we 
find at the present time the best authorities on the subject 
of glanders and on clinical diagnosis. 

The Bureau of Animal Industry, in consideration of the 
favorable results obtained from this test in other countries, 
has for a period of more than a year carried out extensive 
investigations with a concentrated maliein. For this 
purpose the cooperation of official and practicing veteri- 
narians was solicited in various parts of the country. 
Ophthalmic maliein was furnished to all practitioners who 
desired to make a careful study of the method and establish 
its comparative value with other tests for glanders, espe- 
cially the subcutaneous maliein test. In this experimental 
work about 18,000 horses have been subjected to the 
ophthalmic test, and in most cases it has been applied 
simultaneously with the subcutaneous maliein test. The 
data collected from the reports of a gi-eat number of veteri- 
narians indicate satisfactory results from the eye test, and 
those who employed the method appear to be unanimous 
in their preference of the eye test over the subcutaneous 
test. 

The comparative diagnostic tests for glanders which 
have been carried out by the Bureau of Animal Industry 
in connection with immunization experiments in glanders, 
and in several outbreaks of the disease, proved the eye 

29686—14 



test to be reliable and most practicable. In most of these 
instances the results were controlled by post-mortem 
examinations. 

As a result of these favorable findings the bureau has 
decided to recognize this method of diagnosis for the 
interstate shipment of equines. 

This method has a great advantage over others by its very 
simple application. It may be readily executed by any 
veterinarian, and its other advantages are that the results 
are obtained in a comparatively short time and are, as a 
rule, distinct and definite. The simplicity of its applica- 
tion is plainly manifest when compared to the subcuta- 
neous test, as it is only necessary to drop into one of the 
eyes of the animal to be tested 3 drops of concentrated 
mallein or, by a still simpler procedure, to dip a camel's- 
hair brush into mallein and introduce this into the con- 
junctival sac of the animal. The reaction usually com- 
mences in 5 to 6 hours after the introduction of the mallein, 
and lasts from 24 to 36 hours. A positive reaction is mani- 
fested by a purulent secretion from the tested eye. This 
may be very profuse or slight, sometimes associated with 
a severe conjunctivitis and edema of the lids and at other 
times without any inflammatory symptoms being present. 
At times only a very small quantity of pus may be present 
in the inner canthus of the eye. At other times the reac- 
tion may result in a true pyorrhea. The reaction manifests 
itself in varying degrees in different animals, but the in- 
tensity of the reaction has no relation to the extent of the 
disease in the reactor. 

The essential factor in obtaining satisfactory results from 
the test appears to be in the use of the right kind of mallein. 
It must be by all means a concentrated mallein, and appar- 
ently the best results follow the use of raw or precipitated 
mallein, the former representing the mallein obtained after 
the concentration of the filtrate from the bouillon cultures 
of the glanders bacilli. The ordinary mallein used for sub- 
cutaneous testing is not adaptable, and the few failures 
which have been reported in the literature were due to 
the fact that the mallein employed was not sufficiently 
concentrated. 



INSTRUCTIONS FOR APPLYING THE OPHTHAL- 
MIC TEST. 

Before the application of the ophthalmic test the animals 
should be carefully examined to ascertain whether the 
eye shows conjunctivitis or other changes which are asso- 
ciated with suppuration. Should such be present, the 
test should not ha applied. 




An average reaction to the ophthalmic test. 

Th9 test consists in introducing into the conjunctival 
sac of the eye several drops of either undiluted raw mal- 
lein or a solution of precipitated mallein (0.1 to 0.2 c. c. 
per horse). This may be introduced either with the aid 
of an eye dropper or preferably with a camel's-hair brush 



by applying the brush gently along the inner surface of 
both the upper and lower eyelids. The other eye is not 
treated, but servee as a control for comparison of the re- 
action. For the tasting of horses in the same stable the 
same dropper or camel's-hair brush may be used for all 
animals, but the dropper or brush thould be sterilized 
before use upon different lots of horses. 

As soon as the mallein is introduced into the eye prac- 
tically all animals show a lacrimation, increased redden- 
ing of the conjunctiva, and slight photophobia. No sig- 
nificance should be given to these symptoms. They 
disappear in one or two hours. A pseudo-reaction can be 
produced by artificial or accidental irritation of the eye. 

The characteristic manifestation of the reaction for 
glanders commences as a rule from 5 to 6 hours and lasts 
24 to 36 hours, sometimei: longer. It consists of a purulent 
discharge from the conjunctival sac which is typical and 
is frequently associated with reddening, swelling, and 
gluing of the eyelids. It is advisable to examine the 
tested animals in a good light from 12 to 24 hours, or pref- 
erably 16 hours, after the application of the test. 

A suppurative discharge of varying quantities is con- 
sidered a positive reaction. The conjunctiva and the eye- 
ball should also be included in the examination after 
examining the discharge. By removing the purulent dis- 
charge (either by the stable attendant or by the animals 
licking each other, etc.) the positive result may be obliter- 
ated. In such cases dried pus may be frequently found 
on the parts around the eye, or the exposure of the con- 
junctiva by means of pressure by the thumb and finger 
will show fresh, purulent material. 

Generally the positive ophthalmic reactions are not 
accompanied by fever or systemic disturbances. Occa- 
sionally, however, affected horses are hypersensitive to 
such a degree that even the few drops of mallein placed in 
the eye may enter the circulation and produce fever. 
Therefore, it is advisable, when possible, to accompany the 
ophthalmic reaction with temperature readings. For this 
purpose the temperature should be taken twice, the first 
time when the eye test is being made, and the second time 



when it is judged. In a doubtful eye reaction where there 
is an increased temperature of 1^° F., the test should be 
considered positive if the animal had a normal tempera- 
ture at the time the test was made. 

In the absence of any secretion the test should be con- 
sidered negative. When there is a mucous secretion or 
lacrimation during the period of reaction the test must be 
considered as atypical, and in such cases it may be 
repeated the same day, when as a rule the results are more 
confirming. 

The application of the ophthalmic test should not be 
repeated more than three times on the same animal within 
a short period, as experiments show that the reaction after 
the third application made within three months usually 
loses its intensity in positive cases and on subsequent 
tests may be entirely absent. In cases where the results 
of the second test immediately following the first test are 
atypical, the blood of such animals may be drawn and 
forwarded to a laboratory for the serum diagnosis, as the 
instillation of ophthalmic mallein does not influence this 
method of diagnosis. From experience gained with the 
eye test such a procedure would become necessary only in 
a comparatively few cases. In the control of glanders, 
animals may be retested every six months with satisfactory 
results. 

The mallein for the eye test is a clear, sirupy, dark 
brown liquid, gi\dng off a rancid, disagreeable odor. This 
mallein is supplied in small vials of three sizes containing, 
respectively, 1 cubic centimeter, 2 cubic centimeters, and 
3 cubic centimeters of mallein. One cubic centimeter is 
sufficient for testing 10 horses. Each bottle is dated, and 
the mallein is not recommended for use longer than three 
months after the date on the bottle. The bureau will be 
in a position to fill orders promptly, therefore only suffi- 
cient amounts for immediate needs should be requested. 
Partly used bottles should not be kept over from one day 
to another. The portion of mallein unused at the end of a 
day should be discarded. 

o 



LTa3'iora Bros. 

Makers 

Syracuse, N. V 

PAT. JAN, 21. 1908 



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